#include<cstdio>
#include<cmath>
using namespace std;
int main(){
    int s=0;
    char ch;
    while(scanf("%c",&ch))
    if(ch=='\n')break;
    else s+=ch;
    while(scanf("%c",&ch))
    if(ch=='\n')break;
    else s-=ch;
    printf("%c",abs(s));
    return 0;
}
